This invention relates to an impact absorbing net and a method for absorbing impact which attenuates an impact of a snow avalanche, falling rocks, etc. and stops the same.
In a conventional rockfall protection fence, a plural number of horizontal ropes are horizontally stretched between posts provided on a slope. The strength of the posts and the horizontal ropes receive and stop the rockfall. Vertical ropes may be crossed with the horizontal ropes to form nets to prevent the horizontal ropes from spreading open due to the rockfall. Clamps may be provided at the crossing points of respective horizontal ropes and vertical ropes, so that the impact may be attenuated by the frictional resistance caused by the sliding of the ropes in the clamps.
The ropes may be curved. Both ends of the respective rope may be fixed together to form a ring. Then, the inner circumference of each of the respective rings is designed to be in contact with the inner circumference of other rings, thereby forming a chain net. This type of net is disclosed in Japanese Opened Public Patent Application Number Heisei 8-53814 and Japanese Patent Application Publication Number Heisei 10-88527.
In the above-described conventional structure, an impact energy of the falling rocks, etc. is to be received by the strength of the ropes, and is attenuated by the stretching of the ropes or by the frictional resistance caused by the sliding of the ropes in the clamps. Under this method, in order to attenuate a large impact energy, a rope with a larger diameter, a different clamp to increase the force to hold the rope, etc., are used to create a larger frictional resistance caused by sliding. However, using these types of devices or methods not only increases the cost but also is impractical because of its ineffective assemblability and useability.